Only fill in holes if storing the number to the double array has succeeded.

src/x64/stub-cache-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4090 matching lines @@
     // rcx: key
     // rdx: receiver
     // rdi: elements
     // Initialize the new FixedDoubleArray. Leave elements unitialized for
     // efficiency, they are guaranteed to be initialized before use.
     __ Move(FieldOperand(rdi, JSObject::kMapOffset),
             masm->isolate()->factory()->fixed_double_array_map());
     __ Move(FieldOperand(rdi, FixedDoubleArray::kLengthOffset),
             Smi::FromInt(JSArray::kPreallocatedArrayElements));
 
+    // Increment the length of the array.
+    __ SmiToInteger32(rcx, rcx);
+    __ StoreNumberToDoubleElements(rax, rdi, rcx, xmm0,
+                                   &restore_key_transition_elements_kind);
+
     __ movq(r8, BitCast<int64_t, uint64_t>(kHoleNanInt64), RelocInfo::NONE);
     for (int i = 1; i < JSArray::kPreallocatedArrayElements; i++) {
       __ movq(FieldOperand(rdi, FixedDoubleArray::OffsetOfElementAt(i)), r8);
     }
 
-    // Increment the length of the array.
-    __ SmiToInteger32(rcx, rcx);
-    __ StoreNumberToDoubleElements(rax, rdi, rcx, xmm0,
-                                   &restore_key_transition_elements_kind);
-
     // Install the new backing store in the JSArray.
     __ movq(FieldOperand(rdx, JSObject::kElementsOffset), rdi);
     __ RecordWriteField(rdx, JSObject::kElementsOffset, rdi, rbx,
                         kDontSaveFPRegs, EMIT_REMEMBERED_SET, OMIT_SMI_CHECK);
 
     // Increment the length of the array.
     __ Move(FieldOperand(rdx, JSArray::kLengthOffset), Smi::FromInt(1));
     __ movq(rdi, FieldOperand(rdx, JSObject::kElementsOffset));
     __ ret(0);
 
@@ skipping 16 matching lines @@
     __ jmp(ic_slow, RelocInfo::CODE_TARGET);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64